Thermostatically operated valve mechanism



P w. L. HAWK ErAL 2,358,637

THERMOSTATICALLY OPERATED VALVE MECHANISM Filed Nov. 1'7, l941 2 Sheets-Sheet 1 7& 46

Sept. 19, 1944. w. 1. HAWK ETA].

THERMOSTATICAIJLY OPERATED VALVE MECHANISM v Filed Nov. 17, 1941 2 Sheets-Sheet 2 57 11/? f7 4 IE EL F' IIIIIIIIIIIII/d INVENTOR 14/0/50 1. fiat v; BY flog 60 WZOI) Patented Sept. 19, 1944 THERMOSTATICALLY OPERATED" vA'IQV E ECHANISM Watson- L. Hawk and Roy N. Bowmanystockton,

assignors .to Rheem Ma-nufacturing Company, Richmond, Calif.,-a corporation .of

California Application November 17, 1941, serial- No.:419,444

' Claims. (01.23648) The invention relates to thermostatically operated snap-acting valve mechanisms and more particularly to the construction of the clicker or snap-acting device and valve combination.

Inthe thermostat art, various; types ofsnapacting or so-called' clicker devices have been used in the chain of movement between-a temperature responsive element and a control member such as a valve or switch. Many devices, however, which are successful'for moving a contact arm of an electric switch with-snap-action, are not successful for opening and closing a valve for the reason that in the latter case a great deal more force and poweris required to open the valve with snap action to overcome the greater inertia of the valve parts andthe resistance of the usual fluid back pressure andvalve closing spring urging the valve to its seated or closed position. 'An object of the present invention is to provide a clicker device of the character described which although very' simple in its construction-and operation, will nevertheless possess sufiicient power in its sn-ap movement to properly open' a gas valve andto hold the valve in open position.

Another object of the invention is to provide.

axsnap actingmechanism of the character described Which will have sufficient throw to insure an abundant flow-of gas through the open valve.

' A further object of the 'inventi'on is to provide a mechanism of the character described having improved sensitivity therebyafiordin a so-called :short range thermostat operating 'upon a tem perature-difierential of well under Fahr.

going, will beset forth in the following description of the preferred form. of. the inventionwhich is illustrated in the drawings'accompanying and forming part of the specification. It is to be understood, however, thatvariations in the showing madev by the said drawings and description clicker strip.

may be adopted within the scope 'ofthe invenline 3 3 of Figurel. v 5 V g fFigureA is a vertical sectional view taken-at substantially right angles to the plane of Figure 3 garid as indicatedby Figure 3. p w r I V 'Figur'efi i 'a cross sectional View of the-mechanism taken substantially'on the plane of line Figure 6 is 'ajplan'view" of the clicker-strip used in the present mechanism.

Figurefl is 'a' longitudinal edge view-oi the Figure '8 is an' end" eleva'tionof the clicker strip. j 1 W Figure '9 'is"aside"elevation of the" clicker strip as shown in a snapped position with respect to "Figures, 6 8.

. Figure 10" is an end elevation "of "the clicker strip'in its snapped position g a .Figure 11 is'a vertical sectional view of a modifiecl form of construction of the mechanism.

' Figure 12 isa 'verti cal sectional view taken at substantially right angles tothe'plane oIFigure 11 and ,asindicated by'the plan of-line l2-"l2 offigure11. W H v V g g V Figure 13 is across-sectional view ofthe modified'formof mechanismand is taken substantial ly on the plane of line l3'of Figure 12.

'Fig'ure 1'4 is a v'ertical sectional viewofa further modified formof theinvention. V

Figure 15 is-aplan viewof the clicker strip used in the mmof theinvention illustrated in Figure14..:

The thermostatically operated gas-valve'-mech' anis'm of the bresent-invention consistsfibriefly 'of a 'snap' a'cting devie consistingof-a strip-of re- 'sllient' material bent along 'a transverse axisgto define intersecting planar portions, the combination; of temperature responsive rneans and-an abutment engaging one of these portions and-op erative' upon an increase in temperature to arch the portion in intersecting relation to the trans;

verse bend; whereby theoppo'siteend portion of the strip is ceu ew -t ona :i'rltd a' '*s'traight=' li ne position with the first portion with thesnapping end portion arched in conformity with the first portion so as to form a straight rigid longitudinal member, and an organization of parts including a valve and means connecting the valve to the free end portion of the strip and arranged whereby such end portion in snapping to its straight arched position, will open and hold open the valve. Other important features of construction will appear in th following detailed description of the mechanism.

With reference more specifically to the accompanying drawings, the thermostatically operated gas valve mechanism is housed in a casing l6, here formed as a cast body, (see Figures 1 and 2) having two main portions l1 and I 8 each of hollow construction and connected by a hollow bridge piece IS. The body portion I8 is formed at the lower end thereof with a gas inlet opening in which is fitted a gas supply conduit 2!, and is further provided in the interior thereof .with a valve chamber and a manual shut-off valve, not shown, operated by a handle 22 at the top of th body portion [8. Above the shut-off valve, the hollow passage 23 in the bridge portion 19 connects with the interior gas passage in the body 18 and leads off laterally through the bridge piece l9 into a valve chamber 24 at the front of the body portion l1; :A pilot gas passage also leads off from the interior gas pas-' sage of the body portion 13 above the shut-off valve and a conduit 26 is connected to the body for conveying gas to the pilot burner. Also preferably, a pilot shut-oil valv is incorporated in this latter passage and operated at the exterior of the body by means of a lever 21, The construction of the body portion [8 and the several passages and valves. above mentioned, form no part of the present invention and are more or less standard construction and practice and hence a detailed showing of. the same has not closed on th front sidethereof by a plug 28 threaded into the chamber, and that the gas is discharged from the chamber byway of a plurality of discharge openings 29 provided in the base wall- 3 l' of the chamber about a central valve :stem support 32. 'Formed in the base wall 3I around the openings '23 and facing into the chamber, is an annular valve seat 33 which is adapted to engage the forward face of a valve 34 mounted in the 'chamber between the seat 33 and the insidewall of the plug 28. A helical spring 36 is compressed between the plug and the valve fornormally urging the valve to the seat 33. The valve is mounted for movement to and from its closed position against the seat 33 by means of a, valve stem3'l carried by the valve axially thereof and mounted'for reciprocation through a cylindrical opening provided in the valve stem support 32, the opposite free end 38 of the valve stem projecting through the support 32 and into an adjacent interior compartment 39 in the body portion for operation by the valve opening means. Gas is discharged from the compartment 39 in the open position of valve 34 by way of an opening 4| in the base of the body, and towhich is connected a conduit 42 customary manner by means of a rod and tube thermostat including a tube 46 of copper or other heat expanding metal and a rod 41 of ferrous (invar) metal or other material having a low coefiicient of heat expansion. The tube 46, as will be noted, is threaded into a passage 48 centrally through the plug 44 so as to rigidly secure the inner end of the tube to the body, the majority of the length of the tube thereby projecting from the plug for direct engagement with the hot water in the tank. The rod 41 extendsaxially through the tube 46 and the outer end of the rod is fastened to the outer end of the tube whereby the rod and tube move as a unit thereat, thereby producing a relative movement between the inner end 49 of the rod leading to the gasburner of th heating system and'the inner end of the tube and the body. By reason of this construction and as will be readily understood, an expansion of the tube 46 caused by an increase of temperature of the water in the tank will cause a movement of the inner end 49 of the rod to the right, as viewed in Figure 3, and contrawise a contraction of the tube 46 caused by a cooling of the water in the tank will cause a movement of the inner end 49 of the rod to the left.

In accordance with the present construction, means is provided for transmitting the relative movement of the inner end of the rod to the valve 34 whereby upon cooling of the water in the tank to a predetermined temperature, the

valve will be opened to fire the burner under the waterheater and when the water in the tank has been heated to a predetermined tem- \perature, the valve will be closed. Due to the fact that the available movement at the inner end 49 of the rod is relatively small compared to the necessary movement of the valve, the rod movement is amplified in its transmission to the valve and also for reasons Well understood in the art, a snap-acting device is incorporated in the chain of movement so as to cause the gas valve 34 to snap open and to snap closed after the rod end 43 hasmoved a predetermined distance.

The snap-action device, or as sometimes referred to as the clicker, consistsof a sheet or strip 5| of resilient materialsuch as spring steel and is bent along a transverse line or axis 52 so as to define substantially planar end portions 53 and 54 which intersect at the transverse line 52. 'We have found that best operation of the clicker is obtained when the planar portions 53 and 54 are disposed at an obtuse angle with respect to line 52 of approximately 167, as illustrated in Figure '7. Now if distorting forces are applied to one of the planar portions, such as portion 53, so as to cause the latter to arch or curve about a longitudinal line or axis 56, the arch formed'in the portion 53 will intersect the transverse line of bend of line 52 and if the portion 53 is arched sufficiently, the opposite end portion 54 will spring into a straight line position along the longitudinal axis 56 and be held in arched form continuous with portion '53.

- As the distorting forcesappliedi-to portion. 53

portion 53are illustrated as F1 and F2 depress-' ing the opposite edges of the strip portiorr 53 and-F3 operatinginan opposite direction at the center of the strip. The efiectingof the arching of themember isillustrated in Figure 10. In accordance with the present invention the forces F1, F2 and F3 are continuously applied in accordance with and proportional to the thermostatic movement of the rodend 49, while the movement of the opposite end portion 54*of'the strip is sudden and discontinuous and effected only after forces F1, F2 and F3 have moved a predetermined distance. v

'With reference to Figures 7'to 10, it will be noted that the forces F1, F2 and F3 move but a relatively small distance to produce a substantially greater movement of the free end portion 54=of the strip,- whereby amplification of movement' is obtained. We have also found that the operation of the strip is substantially improved when the free end portion 54 is narrowed in width toward the free end 51" thereof: Thus we prefer'to taper the side edges 53 and 59 of the end portion 54 from the bend line 52 towards the free edge 51. r I

While the strip provides a positive snap action throw of the-end portion 54 in opposite 'direc tions as aforementioned, We have found that the portion 54 moves into its arched straight line position, as illustrated in Figures 9 and 10, with considerably more vigor than its return snap-movement to its normal planar position, as-illustratedinFigures 7 and 8. In itsarched position; the end portion 54 is .very rigid'to later allyapplied forces'by reason of its archedconformation. As above mentioned, in the opening and closing of a gas valve of the present character, a substantially greater force and more energy'is required to open the valve with snap action than toclose the valve with snap action, by reason of thegas pressure and 'valve closing spring both operating to urge'the'valve to its seated position and to hold the valve in seated position. In view of the foregoing andas an important feature of the present construction, the'clicker mechanism isso arranged as to; produce an opening of the'valve 34 upon snap movementiof end portion 54 to its arched straight line, positionjwhereby the maximum force and energy ismade available for opening the valve.

Applying the above to the present structure; and with special'reference toFigu'res 3, 4 and 5, it will be noted that the base portion 53 of the strip is mounted centrally thereof on a relatively narrow abutment 6| which extends longitudinally centrally ofthe strip. The base portion 53 may be secured to the abutment-in any desirable manner, as for example by, means of-a screw 62,. here threaded into the abutment andengaging through an opening 63, ingthe strip. As will beseen from Figures .3 ancl 5,,the abutment -6l is formed as an integral portion of the front-wall of the casing and is arranged; in. longitudinal alignment with-the valve; .stem 31,- :whereby with 3301? the valve stem for engagement with the strip portion 54. In this instance-the abutment fil servesto' provide force Ft; as' illustrated in Figures 8 and 10,-and by reason of the narrowness of the abutment, see Figure 5, the side edges GB- 'and 6 73 ofthestrip portion 53 are unsupported and may be moved in the direction of the abutment to arch the base portion of the strip as above described. r v

'Ijhe depressing forces on the side edges- 66 and 61 of the strip, and corresponding to forces F1 andFz, illustratedin Figures8' and 10; are here provided'by means of a movement' ampli fying lever 68 operatively connected-toand actuated by the end 49 -of-the rod. As will be seen from Fi'gure 3, one end 69-of the lever is mount ed on a fulcrum ll, while the opposite end is formed with side projections 13, see Figure 5; which engage thestrip adjacent the side edges 66 and 51 to force the strip into an arched position 'over theabutment 6|. The lever is engaged intermediate its length by the free end 49 0f the thermostat rod whereby-amplification of movement is' ob'tained.

In the operation of the device, when the water in the storage tank has been heated to a pre determined temperatura the rod end '49'willbe movedto the right andthestress on the base portion-"53.- of the-strip released-sufficiently to permit the o'pposite'end' portion 54-of the strip to assume'its normal planar position, thereby permitting thevalve 34 to seat and close oifthe gas-flow to the burner. Asthe'water inthe tank begins to cool, the rod end 49 of the thermo'- statis-forced tothe left,- thereby urging the base portion-53 of the strip to its arched posi-n tionand when this movement has continued to apoint of instability ofthestripLthe freev end portion 54 of the strip will rapidly snap over into the straight line position aforementioned and. open valve 34. In order to obtain a proper open-'- ing and closing of the valve, we have found that it is desirable to limit the throwing movement of? strip end 54*to something less than its full throw' if unrestricted. This means is here in the form of a bracket I4 which is mounted under the free extremity 51' of the strip and is of channel form in-cross section, as viewed in Figure 3, so as to limit the throw of the strip end 51 to the internal dimensions of the channel.

As an important feature, of the present construction we provide means for adjustingthe device to operate at'various predetermined temperatures, so that the water in the tank may be maintained at any desiredtemperature within the range of operation of the device. Such an adjusting means is here effectively provided by the provision of adjusting the position of. fulcrum 1|,whereby the relationship of the longitudinal position of rod end 49 and the stress on the strip may be adjusted and controlled. As here shown, the fulcrum H is provided on the end of a screw member 76 threaded through a wall of the casing and end Ti to permit adjustment; As will be understood, a threading of the, screw into thebody Will-displace the lever toward the end of the rod engageable at its outer I whereby the latter at higher temperatures will cause the strip to snap over, and contrawise an unthreading of the screw 16 from the body will retract'the-lever from the rod, thereby shifting thecritical movement of the rod,,and the cor-. responding snapping of the strip, to a point to the left or at a lower temperature.

will be clear from the foregoing, theprovision of an organization of parts wherein the rclicker strip operates to strike the valve stem :and move the valve-to open position in the snap movement of the strip to its arched position, liakes advantage of the strongest and most powr rerful movement of the strip 1 for opening the 'valve. In this manner, and notwithstanding the use of a relatively light weight strip member, we obtain sufficient snap acting force to insure a :rapid snap opening of the valveand the maintaining of the valve in open position until relle ased by the strip. It will further be noted that :the free end portion 54 of the strip is of sub- ;stantial length, whereby the same moves through :aconsiderable length in its snap movement, thus insuring a sufficient opening of the valve. for :abundant gas flow. As another important feature of the construction, and as mentioned in the foregoing, there is sufficient amplification of movement in the chain of movement from the rod to the valve to obtain desirable sensitivity of the apparatus. Where desired the present apparatus can be designed to operate well under a Fahr. temperature variation. While the apparatus possesses a high degree of sensitivity, the same may nevertheless be subjected to very widetemperature variations .without injuring the mechanism; As will be seen from Figure 10 of the drawings, the strip may be 'arched well beyond its operating positionwithout injuring the strip as might occur should the device be subjectedto temperatures far below the operating temperature to which the mechanism is set.

A modified form of the invention has been illustrated in Figures 11 to 13.wherein the clicker device asabove described with slight modification has been adopted for use in a safety pilot 7 shut-off valve mechanism. In such a construcof fulcrums 92. In this embodiment, the clicker strip 5l' is supported at the rear wall 43' of, the compartment 39 and is engaged by the lower end 12' of the amplifying lever 68', the latter being fulcrumed against the rear wall at its upper end 90 whereby upon expansion of tube 46' andcorresponding tensioning of rod 41', the lever will be rotated in a counterclockwise direction, as viewed in Figure 11, to apply an operating force to the base part 53' of the clicker strip. In this form of the invention the base portion 53' of the clicker strip is supported against a pair of transversely spaced abutments 96 and 98 which engage the strip adjacent the side edges 66' and 61- thereof, and the lever end 12' engages the strip centrally between the projections 96 and 98, whereby upon movement of the lever against the strip, the latter will be forced to an arched straight line position as above described to open'and hold open the valve 34'. In accordance with the foregoing and with reference to Figure 11, it will be seen that so long as the pilot burner remains ignited the rod 41' will be placed in tension, drawing the collar 9| against the lever thereby holding the strip in its straight line valve opening position. Upon extinguishment of the pilot flame, and attendant cooling and contraction of tube 46, the force on the strip will be released thereby permitting the same to assume its normal bent position as shown in full lines in Figure 11, thus permitting the valve to move to its seated position under the influence of the gas pressure and the valve closing spring. It will be noted in this adaptation of the invention that a severe cooling of the instrument can at no time subject the clicker strip to an unreasonable distorting force because the colder the instrument the less force 7 is applied to the clicker strip.

tion the thermostat tube 46 is mounted in juXtaposition to the pilot burner of a main gas burner and is heated by such pilot burner and is operative upon accidental extinguishment of the pilot burner to contract and cause; the closing of a valve 34' in the main burner gas line to thereby prevent the flow of gas to such main burner until the pilot light has been reestablished. One principal difference between this form of device and that illustrated in the embodiment of the invention above, is that the rod '41 in the safety pilot shut-off is operated in tension rather than in compression, as in the first form of the invention. outer end 11 of the rod is threaded into a receiving socket 18 in the outer end 19 of the ther mostat tube 46', whereby thelongitudinal position of the rod in the tubemay be adjusted by relative rotation, thus determining the operating temperature of the device. The opposite end 8! of the rod projects from the inner end 82 of the tube into the interior compartment 39 'of the body and passes throughan opening in an amplifying lever 68' intermediate'the latters length and is operatively connected to the lever at the forward side thereof by means of a collar- SI' [pinned to the rod and engaging the forward side of the lever through the medium As will be seen from Figure 11 the In this form of the inventionas in the previous form, the opening movement of the valve and the amount of movement permitted the free end portion of the. strip, is preferably adjustably controllable. As will be seen from Figure 11, the lower end of the strip is here confined between the head 99 and the screw IM and the end I02 of a sleeve I03 carrying the screw and in turn threadably carried by the'rear wall of the body. The position of the end I02 of the sleeve is fixed by means of a lock nut I04 mounted on the sleeve and engaging the wall, and the position of the head 99 of the screw is determined by the relative threaded engagement of the screw and sleeve. As aforementioned, the spacing between the screw head and the sleeve end is preferably adjusted to something less than the fullnormal throw of the free end of the strip.

A'further modified form of the invention has been illustrated in Figures 14 and 15 wherein the clicker strip I06 is so arranged that a distorting force applied to a center portion I01 thereof will cause the end portions I08 and I09 to move with snap action; whereby movement may be taken from bothends of the strip. As here shown, the end portions' I08 and I09 are bent from the plane of the center portion I01 along spaced transverse lines or axes III and H2 whereby the arching of the center portion I01 about a longitudinal line or axis II3 will cause the end portions I08 and I09 to spring into a straight line arched position. With reference to Figure 14, it will be seen that the center. portion I01 is mounted upon a central abutment 6|" and is operated by a movement amplifying lever 68", as in the first embodiment, and the end portions I08 and I09 are arranged in juxta-position to a yoke member H4 secured to the valve stem 31{. The amount of movement permitted the free ends H38 and I09 is limited by a bracket member H6 having channel portions Ill and H8 arranged about the free strip ends in a similar manner to that shown in connection with the first embodiment. In this form. of the invention it will be noted that as the water inthe tank is heated to a predetermined temperature, the distorting force on the center portion of the disc is relieved whereby the strip end portions I08 and H19 spring to their normal position, thereby permitting a seating of the valve 34". On the other hand as the water in the tank cools, the distorting force is applied to the center portion ID! of the disc, causing the latter to arch along line or axis H3 and after a predetermined distortion of the center portion, the strip end portions I08 and N9 will spring into a straight line arched position thereby striking and displacing the yoke I I4 and opening the valve 34" with snap action.

We claim:

1. In a snap acting mechanism for opening and closing a valve, a sheet of resilient material having substantially planar portions intersecting along a substantially straight line, temperature responsive means and an abutment engaging one of said portions and operative upon a change in temperature to arch said portion in intersecting relation to said line whereby to cause said other portion to snap into a continuous arched Dosition with respect to said first portion, and an organization including a valve and means connecting said valve to said other portion arranged whereby said portion in snapping to arched position will open and hold open said valve, said other portion having a free end and a stop engaging said free end in one of the positions of said other portion.

2. In a snap acting mechanism for opening and closing a valve which is spring-pressed to assume a closed position, a sheet of resilient material having substantially planar portions intersecting along a substantially straight line, temperature responsive means and an abutment engaging one of said portions and operative upon a change in temperature to arch said portion in intersecting relation to said line whereby to cause said other portion to snap into a continuous arched postion with respect to said first portion, and an organization including a valve and means connecting said valve to said other portion arranged whereby said portion in snapping to arched position will open and hold open said valve against the resistance of the valve spring,

said other portion having a free end, and a stop engaging said free end in one of the positions of said other portion.

3. In a snap acting mechanism for opening and closing a valve which is spring-pressed to assume a closed position, a sheet of resilient material bent along a transverse line to provide substantially planar portions intersecting at said line, temperature responsive means and abutment means engaging one of said portions and operative upon a change of temperature to arch said portion in intersectin relation to said line whereby to cause said other portion to snap into a continuous arched position with respect to said first portion and upon a reverse change in temperature to permit return of said first portion towards its planar position whereby said second portion will snap into its normal inclined planar position, said second portion being adapted for connection to said valve for opening same against the resistance of the spring when said first portion is arched as aforesaid and closing the valve upon snap action of said second portion in reverse direction, said second portion having a free end and means for controlling the amount of valve opening comprising a stop engaging the f having spaced pressure'points engaging said first portions adjacent the transverse edges thereof on opposite sides of said supporting means to cause an arching of said first portion about said supporting means and in intersecting relation to said axis to produce a sudden movement of said other end portion into a substantially straight line arched position with respect to said first portion.

5. A thermostatically operated gas valve comv prising, a casing having a valve compartment defined in part by the front wall of said casing, a gas valve mounted in said compartment and supported for movement to and from a seated passageclosing position, a valve stem carried by said valve and extending axially therefrom, an elongated strip of resilient material being bent along a transverse axis to provide substantially planar end portions inclined to each other, means along the longitudinal center of the strip for supporting one of said portions on said front wall with the other of said portions in juxtaposition to said valve stem, a screw member threaded through said front wall in substantially aligned position with respect to said valve stem and said supporting means, a lever having one end thereof fulcrumed upon the inner end of said screw member and the opposite end thereof engaged with said first strip portion and having points at opposite sides coacting with said supporting means to, distort said first strip portion into an arched form intersecting said axis to cause snap action of the opposite end portion of said strip, and a thermostatic element movable according to temperature changes carried by the rear wall of said casing and adapted for mounting within a hot water tank or the like and having one end thereof engaged with said lever to produce the aforesaid distortion of said first strip portion.

WATSON L. HAWK.

ROY N. BOWMAN; 

